On the orientation of the pulsar space velocity vector relative to the spin axis

Abstract

It is noted that the angle between the space velocity vector and the spin axis projected on the plane of the sky has a value close to zero deg for three pulsars, close to 90 deg for six others, and between zero and 90 deg for two more. A hypothesis that could explain how these different orientations arose is presented which involves three modes of pulsar formation. It is suggested that pulsars formed in supernova explosions of single stars should have angles of approximately zero deg, that pulsars with angles close to 90 deg were liberated from binary orbits disrupted by supernova explosions of their companions, and that pulsars with angles between zero and 90 deg were produced by supernovae of their own progenitors in (subsequently disrupted) binary systems.